getTopPerformer.js

export function getTopPerformer(breakdown, num_days) {

    const changeArray = []

    for (let i = 0; i < names.length; i++) {
        const changeObj = {
            name: names[i],
            change: (breakdown[breakdown.length - 1][names[i]] -
                    breakdown[breakdown.length - 1 - num_days][names[i]])
                    / breakdown[breakdown.length - 1- num_days][names[i]]
        }
        changeArray.push(changeObj)
    }

    // Find maximum value and its corresponding index in changeArray
    let maxValue = -Infinity;
    let maxIndex = -1;

    for (let i = 0; i < changeArray.length; i++) {
      if (changeArray[i].change > maxValue) {
        maxValue = changeArray[i].change;
        maxIndex = i;
      }
    }

    // Change %
    const maxChange = maxValue * 100;

    // Round off to first digit after decimal
    const roundMaxChange = Math.round(maxChange * 10) / 10;

    const resultObj = {
        maxChange: roundMaxChange,
        maxName: tickers[maxIndex]
    }

    return resultObj

}